Physical Activity, Muscle-Strengthening Activities, and Systemic Inflammation Among Retinopathy Patients

OBJECTIVE. We evaluated the specific association between muscle-strengthening activity (MSA) and accelerometer-assessed physical activity on systemic inflammation among retinopathy patients in the United States. METHODS. Data from the 2005–2006 National Health and Nutrition Examination Survey (NHANES) were used to identify 157 retinopathy patients between 40 and 85 years of age with complete data on select study variables. MSA was assessed via self-report. Participation in moderate-to-vigorous physical activity (MVPA) was determined from objective accelerometer data. Systemic inflammation was assessed using C-reactive protein (CRP), which was quantified using latex-enhanced nephelometry. Nonproliferative retinopathy was determined using Early Treatment Diabetic Retinopathy Study grading criteria, as well as objective retinal imaging assessments using the Canon Non-Mydriatic Retinal Camera CR6-45NM. Individuals were excluded if they had been diagnosed with coronary artery disease, congestive heart failure, heart attack, or stroke. RESULTS. MVPA (β = –0.004, 95% CI –0.007 to –0.001, P = 0.006) but not MSA (β = –0.0001, 95% CI –0.002 to 0.001, P = 0.86) was associated with lower CRP levels. Additionally, for a more substantive 30 minutes/day increase in MVPA, there was a corresponding 0.12 mg/dL decrease in CRP. CONCLUSION. In this nationally representative sample of adults, only individuals who engaged in higher levels of MVPA had lower CRP levels, which is indicative of reduced systemic inflammation. MSA was not associated with systemic inflammation among this cohort. Our findings suggest that MVPA is inversely associated with systemic inflammation among retinopathy patients, which is noteworthy because increased systemic inflammation may facilitate retinopathic severity.